(gu<o co.) DOE/ IOn2079-83 NV/WLS/ESL-1 OPEN-FILE REPORT GEOLOGY AND GEOTHERMAL POTENTIAL NORTH OF WELLS, NEVADA by Paul W. Jewell November 1982 Work performed under contract DE-AC07-80ID12079 EARTH SCIENCE LABORATORY University of Utah Research Institute Salt Lake Ci t y, Utah Prepared for U S Department of Energy Division of Geothermal Energy
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~\'.u+Wt&.. (gu<o co.)
DOE/ IOn2079-83 NV/WLS/ESL-1
OPEN-FILE REPORT GEOLOGY AND GEOTHERMAL POTENTIAL NORTH OF WELLS, NEVADA
by
Paul W. Jewell
November 1982
Work performed under contract DE-AC07-80ID12079
EARTH SCIENCE LABORATORY University of Utah Research Institute
Salt Lake Ci ty, Utah
Prepared for
U S Department of Energy
Division of Geothermal Energy
00E/10/12079-83 NV /vJLS/ ESL-l
GEOLOGY AND GEOTHERMAL POTENTIAL NO RTH OF WELLS, NEVADA
by
Pau 1 \~. Jewe 11
November 1982
Prepared for the Department of Energy, Di vision of Geot hermal Energy
NOTICE
Tni s report was prepa red to document work sponsored by t he United Stat es
Government. Nei t her the United States nor its agent, the Un i ted States
Department of Energy, no r any Federal employees , nor any of their contractors,
subcontractors or t heir employees , makes any \~arranty, express or implied, or
ass umes any l ega l li abil ity or responsibility for the accu racy, completeness,
or usefu l ness of any information, apparatus, product or process disclosed, or
represents that its use would not infringe pr ivatel y owned rights.
NOTICE
Reference t o a company or product name does not imply approva l or
recommendation of the product by the University of Utah Research Ins t itute or
the U.S. Departmen t of Energy to the exclusi on of ot he rs t hat may be sui tab le.
Locat ion map for the Wells, Nevada area ••••••••••••••••• • 4
Geologic map of the area north of Wel ls, Nevada ••••••••• •S
Geologic cross section north of Wel ls, Nevada •• •• ••••• ••• 6
Diagrammatic correlation of the Dalton #1 wel l wi t h Gdrside's (1968) measured Te rt iary section •••••••••• 9
Location of shal low wells in and around Wells, Nevada ••• 20
Piper plot of the rma l and non-the rmal wat er in the Wells , Nevada area ••••••••••. ••• •••• ••••••• •• ••••••• •• • • 23
Subsu rface model in wh ich t hermal wa ter issues along a Basi n and Range fault and migrates l ateral ly benea t h a confi ning aquic1ude ••••••••••••• ••••••• •••• •••••••••• •27
Subsurface model in which thermal wat er rises verticall y t hroughout the Tertiary sediments •••• •• •••••• 28
Subsurface model in which separate sources are hypothes i zed for the thermal water ••••••• ••••• •••• ••••• •29
Data fo r wells in the Wells, Nev ada area •••• •••• ••••• ••• 21
Chemistry of t he thermal water near Wells, Nevada ••••••• 24
Geothe rmometers of the thermal water near Wells, Nevada • • •••• ••• ••• ; fl ••••••••••••• ••• • ••••• •• ••••••• •• ••• 25
Majo r and trace element chemi cal ana lysis of wat er from the Reynolds we ll, Wells, Nevada ••• ••••• •• •••••••••••••• 38
Geophys ica l logs of Dalton #1 0;1 test wel l •••••• In pocket
ABSTRACT
Th e geology north of Wel ls~ Nevada is dominated by approxi mately 2150 m
of Tert iary lacustrine siltstones and conglomerates. The sediments are cut by
a high -a ngle, ra nge-bounding fault and several ass oci ated step fau lt s. Hydro
t he nna1 alteration and sil icification are associated with the high-angl e
faults. Two ages of Quate rnary sediments locally ove rl ie the Tert ia ry sed i
ments.
Lithologic and we1' log anal yses define numerous potentia l aqu ife rs in
the Tert i ary sediments. The shallowest of these aqu i fer s is over l ain by a
t uf faceous silt stone which appears to act as an aquitard for hot water mov i ng
t hrough the aq uifers . Three possible subsurface hydro logic models can be
const ruc ted to explain the spatial relationships of the thermal water near
Wel l s •
Cost-effect ive steps t aken to expedite geotherma l development in the area
mi ght i nclude deepening an ex isti ng domestic well in t he city of Wells to at
least 180 m in order to penetrate the tuffaceous sil t stone aquitard, running
boreho le logs for all existing wells, and cond ucting a shallow t em peratu re
probe survey in the Tertia ry sediments north of Well s.
1
INTRODUCT ION
Recent i nteres t in alternati ve energy applicat ions has prompted a study
of t he geology and geothermal resou rces near We lls , Neva da , a small town of
ab out 1200 people in the northeastern part of the state . Hot springs ha ve
been kn own to exist along the western flank of the Sna ke Mountai ns north of
wel ls for nearl y a century (Adams and Bishop, 1884, p. 192 ). Recent
pub li cat ions discussing these hot sp rings include Garside and Schilli ng (1979)
and Trexler et al. (1979).
The exi stence of two warm wells within 1.5 km of the city has come to
l i ght on ly recen tly. Relat ively high temperatures i n the Dal to n #1 oil test
well (I l3 oe at 1220 m) (236°F at 4000 ft) and a shall ower domestic well (49 °e
at 168 m) (120°F at 550 ft) are not mentioned in any previous pu bl ication on
the geothermal resou rces of Nevada. They were brought to t he at t ent ion of the
Earth Sc ience La bo rato ry /University of Utah Research Institute by Mr . Joseph
Reynol ds, a rancher near Wells and owner of the 168 m domestic we ll. A study
to determine the contro l s of the entire geothermal system nea r Wells was
undertaken as a part of t he Depa rtment of Energy's User Assist an ce Program.
Wo rk on the area proceeded sporadically over a 16-month peri od. An
in iti al si t e visi t by t wo ESL staff members was made in mid-March, 1980 to
make a recon naissance examination of the area and mee t Mr. Reynolds and the
mayor of Wells. Dur i ng June, 1980, cuttings f rom t he upper 869 m (2850 ft) of
th e oi l t es t we re logged at the Nevada Bureau of Mi nes and Geology in Reno t o
help determine the st ra t igraphy of the area. Late r that mont h, three days
were spent mapp ing the surface geoiogy north of Wel ls.
2
GEOLOGY
Nort heastern Nevada is a part of the Basin and Range Province, a tectoni c
regime characterized by rel at i vely t hin cru st , high heat flow, and high-angle
fa ult i ng . Thi s porti on of Nevada also constitutes a major portion of a
conspicuousl y high heat flow area known as the Batt l e Mou ntain high (Sa ss et
al. , 1971) . Geothermal syst ems within the Battle Mountain heat flow hi gh are
related to deep circu lation along faults and are ofte n found to be moderate
t empera ture (9 0- 150°C) resources (Brook et al ., 1979).
Th e ci ty of Well s li es near the headwaters of t he Humbol dt Ri ver between
three Basi n and Range f aul t blocks (Figure 1). Rocks ranging i n age from
early Paleozoic to Terti ary are found in the Snake Mountains t o t he north
(Garsi de, 1968; Pet erson, 1968), t he East Humbol dt Ra nge t o t he southwest, and
t he Wood Hill s -Windermere Hills t o the east (Thorman, 1970). A t hi ck sequence
of Eocene to Pli ocene lacust rine sediments forms aprons aroun d all th ree
ranges . Quaternary all uvi um has accumul ated along the Humbol dt Ri ver dra i nage
and i n t he basins between t he ranges.
Te rtia~y Sediments
Only rocks of Terti ary age and younger are ex posed i n the area of this
study (Figures 2 and 3) . Th e Tertiary sect ion consist s largely of sil t stones,
tu ffaceous siltstones, and conglomerates. Tert iary sediments exposed th roug h
out the Great Basi n are bel i ev ed to range in age fr om Eocene to Pl iocene (Van
Hou ten , 1956) . The Eocene-Oligocene sedimentary and vol cani c rock s near Elko
(Solomon et al ., 1979) and the Eocene-Pliocene rocks of the Ca rl in-Pi non Range
(Smith and Ketner, 19 76) have been dated and ma pped i n detai l . On ly recon
nai ssance strat igraphic work and no age determination have been made of the
Terti ary sediments no rth of Well s (Van Hauten, 1956; Garsi de, 1968; Peterson ,
3
;; ,c·:l :; :. ~ .. : li:tlf!Ch
rl w
115"00'
FIGURE 1 - INDEX MAP OF THE WELLS, NEVADA AREA.
4
I I
Figu re 2. Geologic map of the area north of Wells, N evada
Figure 7 . Subsurface model in which thermal water rises a long a Ba s in a nd
Range fault an d migrates laterally beneath a c onfin in g aquitard.
Symbols and un it d esignations as in Figure 2 .
N co
((
Sec.29 /
~ (( ~ff
Fi gure 8 . Subsurface model i n which thermal water r i ses
v ertica lly t hroughout t he Tertiary s ediments.
Symbols a n d u nit d esignations a s i n Figure 2 .
N t.O
Sec . 2 9 />4
Figure 9 . Subsurfa ce m odel i n w i ch s epa r ate s ources a r e h y p o thesi zed
for t h e t hermal w ater . Hot s p rin gs a re cont ro lled b y a Bas in
a nd Range fault. Wate r i n t he Dalton a n d Reynolds wells
c omes from a n u n k no w n s ou r ce to t h e e ast. Sy m bols a nd unit
d esign a tions as i n Figure 2 .
mi ght be pos si ble.
In Figure 7 hot water is hypothesized to rise up t he Basi n and Range
faul t afte r bei ng heated at a depth of approximately 1. 7 km. This Basin and
Rang e fault exhi bi ts hydrothe rmal alteration and an undetermined amount of
di splac ement. (The amount shown in Figure 7 is speculati ve) . Cool i ng of t he
hydrothermal flui ds in the upper portion of the fault has resulted in silica
de posi t ion and formation of a relatively im pe rmeable zone. Upon encountering
t his rel atively impermeable zone , the water is forced to migrate late rally . A
pos s ib le path for migration wou ld be a porous conglomerat e aquifer immediat el y
beneath the zo ne of hydrothermal alteration. The tuffaceous siltstone which
overli es these conglomerates is believed to form an aq ui t ard whi ch prevent s
the thermal water from escaping to the surface.
The therma l water migrates through fault blocks to t he east an d wes t
(Figure 7). Alt hough displacement along each step fault is estimated to be
ab ou t 150 m (492 ft), the la rge thicknesses and abundance of the congl omerates
rela t ive to l ess permeable sediments permit the wa ter to be t ransmitted
be tween fault bl ock s. The the rmal water that travels to the east moves down
dip t hr ough suc cessive f ault bl ocks, contrary to the shal low, east-to-west
fl owing ground wate r regime of the Humboldt River. On t he other hand, the
t he rmal water t ha t travel s to the west moves up dip, parallel t o t he shallow
ground water reg ime. The result is a stronger hydrau l ic he ad for the geo
the nmal water mov ing west than for the water moving east. The va r ia bl e
hydraulj c head may explain the lack of hot springs east of the Bas in and Ra nge
fau lt •
A second hyd rothermal model (Figure 8) shows thermal wa t er ris ing fr om
dept h throughout th e area north of Wells. The movement of t he wa t er is not
30
st ructurally controlled. In stead, the generally unporous lithol og ies of the
Tert iary sediments al low ve rtical transmission of the thermal wa te r. The
tuffaceous siltstone horizon acts as aquiclude and preven t s much of the hot
water from reach ing the surface.
The thi rd hydrothermal model presumes that thermal water for the hot
springs and the t wo wel ls were derived from separate sources (Fig ure 9). Hot
springs are derived from thermal water fl owing up the Basin and Rang e fau lt
(Figure 2). Thermal water from the Dalton and Reynol ds wells originates from
an eastern source whic h has no known surface manifest ations. Note that in
t his model, circu lation of the thermal water confo rms to the shallow ground
wa ter gradient of the Humboldt River.
Legitimate objections can be raised to each of th.ese models. The fi rst
model implies that the thermal wate r flows i n a director opposite t o t he
shallow ground water. The second model requires that t he hot water move
verticall y th rou gh di verse lithologies, some of whi ch (particularly thos e
below 1060 m) are non-permeable siltstones. The th i rd model is weak because
the nea rest hot sp rings to the east of Wells are located 40 km (25 miles) away
(Trex ler et al., 1979) in a different hydrolngic bas i n (Eakin and Lamke,
1966). All t hree model s suggest the possibility of warm water circulation in
the step fa ults. That no hot springs are seen along these fau1ts is due to
th e fact that the upper portions of these structures ar~ found in the uplifted
Snake Moun tains fault block wh ere they are above t he potentiometric surface.
Another hyd rol ogic enigma is the general absence of warm wa t er in and
arou nd t he town of Wells (Table 1, Figure 5). Two possible explanations are
offered. First, the deepest of the domestic wells in the t own is 111 m (36 4
ft), nearly 57 m (187 ft) above the postulated hot water ent ry zone i n the
31
Reynolds and Dai ton wells. A deeper well within the city l imits mi ght show
the presence of wa rmer water. Secondly, the town is closer to the foot hi l ls
of the East Humbol dt Range and farther away from the hypothesi zed Ba sin and
Range faul t than is the Reynolds property. Runoff from the Eas t Humboldt
Ra nge, t herefore, makes the ratio of cold water to hot wa ter hi gher at Wel l s
t han at the Reynol ds property .
Suggested Exploration Technigues
Several geot hermal exp l oration techniques could be appl i ed to locate
additional ge othe rmal resources or to test the subsurface models hypothesized
i n t he previous discussion. The specific methods appl ied would depend on t he
expl ora tion budget and t he na tu re of the geothe rmal t arget .
Possibly t he most cost -effective technique would be t emperat ure profi l ing
of the exist ing well s. A temperature profile of the Reynolds well would be
very hel pful i n defining the source of the geothermal water, provided t he
fl owi ng artes ian well could be shut in and allowed to ach ieve thermal
equil ibrium. If the Dalton well has not caved, then a new t emperatu re l og
woul d make an inte resting and cost -effective compani on t o the temperature log
shown i n Plate 1. Tempe rature profiles of the shall ow wells in We l ls might
al so be va luable in evaluat ing the thermal ground wa ter regime near the city.
An additional extremely viable exploration techn ique i s a tempe rature
survey usi ng shallow, na"row diameter boreholes. Simila r surveys ha ve been
used 'i n other geothermal areas of Nevada and the western Un ited States.
Excellent acc ounts of the advantages and limitations of t hi s t echn iq ue are
given by 01~steG (1977) and Murphy and Gwynn (1979).
Systematics of a shallow borehole survey are re l at ively strai ght
32
forward. A narrow-diameter hole is drilled to predetermined dept h and PVC
pi pe is inse rted, capped, filled with water~ and allowed to equilibrate
t hermally. A temperature probe is then run down the PVC pipe. The de pt:-: to
whi ch the holes are drilled depends upon the type of geol ogy of t he target
area and the hy pothesized temperature of the geotherma l resource. In general ,
shallow bore surveys are most effective where the unde rlyi ng t hermal anomaly
is large and the perturbing influence of shallow ground water is small.
Reasonably good results have been obtained from surveys as shallow as 1 meter ,
although deeper surveys generall y give better results (Ol msted, 1977). The
te chn ique might be very useful for defining the presence of a thermal an omal y
bel ow the sil ici fi ed zone mapped between Sections 32 and 33 (Figure 2) or for
any exploration in the foothills of the East Humboldt Ra nge. Caution shoul d
be used in applying it near the Reynolds well since the Humboldt River
probably dominates the ground water regime in the Quate rna ry al l uv ium an d
the refore ma sks any thermal anomal y.
Addit ional geophysical metho ds could be brought to bear on the We l ls
geot he rmal resource although their use in this type of geologic sett i ng is
somewhat restric ted . Resistivity surveys are someti mes usefu l in recognizing
subsu rface aqui fers or stream channels. A good aCC8unt of a case history
invo l ving the successful application of the technique is given in Zohdy et al.
(1974). Gravity surveys are also popular in geothermal explorat ion , but t hei r
use is largely restricted to delineating hidden faul ts. The tec hni que mig ht
be useful in the Well s area where the trace Jf the Bas in and Range faul t is
marked by a density contrast such as would be observed between Qu aternary
alluvi um and the Te rti ary sediments.
An active seismic survey was completed prior t o drill ing the Dalton #1
33
ACK NOWLEDGEMENTS
Several co -workers at t he Earth Science Laboratory made valuable comment s
and suggestions du ring the course of this study. I part icularl y wish to
acknowl edge the help and fresh ideas provided by Deb bie Struhsacker, Christia n
Smi th , and Duncan Fol ey. Additional constructive comme nts were offe red by Ted
Gl enn and Denni s Trexler. Analytical work on water samples was done by Ruth
Kroneman. Patr ick Daubner drafted the figures. Georgi a Mitoff and Hol ly
Baker typed the manuscri pt and i t s revisions. Personnel from pet rol eum and
mining com panies working in the We lls area contributed ideas and some data.
The co ncl usi ons and specul ations presented in this report are st r ictl y those
of the author , however.
35
REFERENCES
Adams and Bi shop , 1884, The Pacific tourist: New York,
Brook , C. A., Mariner, R. H. , Mabey, D. R., Swanson, J. R., Guffant i, M. and Muf f ler , L. J . P., 1979, Hydrothermal convect ion systems with reservoi r temperatur es> 90°C, in Muffler, L. J. P., ed., As sessment of geotherma l resources of the United Sta tes - 1978: U.S. Geol ogical Survey Circular 790 , p. 18-85.
Eakin, T. E. and Lamke, R. D., 1966, Hydrologic reconna issance of t he Humbo l dt River basi n, Nevada: . Nevada Department of Conservation and Natural Resources, Wat er Resou rces Bulletin 32, 107 p.
Fourni er, R. 0., 1973, Sil ica in thermal waters: Labo ratory and f iel d investigat ions, in Proceedings of the International Symposi um on Hydrogeoch emi str~and Biogeochemistry, Japan, 1970: Clark, Was hingto n D. C., p. 122-139.
Fournier, R. O. and Truesdell , A. H., 1973, An empir ica l Na-K-Ca geothermometer for natural waters: Geochimica et Cosmochimica Acta., v. 37 , p. 1259 -127 5.
Four nier, R. 0., White, D. E., and Truesdell, A. H., 1974, Geochemica l i ndi ca tors , of subsurfa ce temperature, 1. Basic assumpt ions: U. S. Ge ological Survey Journal of Research, v. 2, p. 259- 262.
Gars i de, L. J., 1968, Geology of the Bishop Creek area , El ko county, Nevada : unpublished Masters thesis , University of Nevada, Reno.
Garsi de, L. J. and Schil li ng, J. H., 1979, Thermal wa t ers of Nevada: Nevada Bureau of Mi nes and Geol ogy Bulletin 91, 163 p.
Gl enn, W. E. and Hulen, J. B., 1979, Interpretation of well l og da ta from four dri ll ho les at Roosevelt Hot Springs KGRA: Un iv. of Utah Research lnst., Earth Scie nce Labo ra to ry Report 28, DOE/DGE Contract ET/ 28392- 27 , 74 p.
Gl enn, W. E. , Chapman, D. S., Fo ley, 0., Capuano, R. M., Cole, D., Sibbett, B., Ward, S. H., 1980, Geothermal exploration program , Hil l Air Force Base, Weber County, Utah: Univ. of Utah Research Inst. , Earth Sci ence Laborato ry Report 34, DOE/DGE Contract ET/ 28392-42, 77 p.
Keys, W. S. and MacCary, L. M., 1971, Application of borehol e geop hysics t o water-resources investigat ions: U.S. Geologi cal Survey Techniques of Wa ter-Re sou rces Investigation, Book 2, Chapter El, 126 p.
Murphy, P. and GNynn, J. W., 1979, Geothermal investiga tio ns at Crystal Hot Spr ings, Sal t Lake County, Utah: Utah Geolog ical and Mine ral Survey,
. Report of Invest i gation No. 139, 86 p.
Oesterl ing, W. A., 1960, Areal economic geology of T37N , R6 1E and 62E , M.D. M.: Land Dept. , Southern Pacific Co., San Francisco, unpubl. map .
36
Ol msted, F. H., 1977, Use of temperature surveys at a depth of 1 met er in geothermal exploration in Nevada: U.S. Geolog ical Survey Professi onal Pape r 1044-B, 25 p.
Olmsted, F. H., Gl ancy, P. A., Harrill, J. R., Rush, F. E. and VanDen bu rgh, A. C. , 1975, Preliminary hydrogeologic appraisal of se l ect ed hydrot he rmal systems in northern and cent ral Nevada: U.S. Geo logical Survey Open-File Re port 75-56 , 267 p.
Peterson, B. J. , 1968, Strati graphy and structure of the Antel ope Peak area , Sn ake Mount ai ns, El ko County , northeastern Nev ada : unpublis hed Maste rs thesis, Unive rSity of Oregon .
Schlumberger, 1972, Log interpretation, vol. 1. - Princ iples: Schlumberge r , Ltd., Houston , 113 p.
Sas s , J. H. , Lachenbruch, A. H., Munroe, R. J., Green, G. W., and Mises , T. H., Jr ., 1971, Heat flow in the western Uni t ed States: Journal of Geophys ical Research , v. 76, p. 6373.
Smi th , J. F., Jr. and Ketne r, K. B. , 1976, Stratigraphy of post-Paleozoi c rocks and summary of resources in the Carlin-Pinon Range area, Nevada: U. S. Geologica l Survey Professional Paper 867 -B , 48 p.
Solomon, B. J., Mc Kee, E. H. and Andersen, P. W., 1979, Eocene and Oligocene l acustri ne and volcani c rocks near Elko, Nevada, i n Newman, G. W. and Goode, H. 0., eds., Rocky Mountain Association o(l[eol ogi sts: Ut ah Geologi cal Association 1979 Basin and Range Sym posium, p. 325-337.
Steve ns, C. H. , 1981, Eval ua tion of the Wells fault, nort heastern Nevada and northwest ern Utah : Geology, v. 9, p. 534-5 37.
Thorman , C. H., 1970, Metamorphosed and non-metamorp hosed Pa leozoi c rock s i n t he Wood Hil ls and Pequop Mountains, northeast Nevada : Geologica l Society Americ a Bul let in , v. 81, p. 2417-2448.
Thorman, C. H. and Ketner, K. B., 1979. West-northwest str ike-slip fa ult s an d ot her st ructures in allochthonous rocks in cent ral and eastern Nevada and wes t ern Utah, in Newman, G. W. and Goode, H. D. , eds., 1979 Basin and Range Symposiu~ Rocky Mountain Associ ation of Geologists: Utah Geologica l Association, p. 123-134.
Trexl er , D. T. , Flynn, T., Koenig, B. A., 1979, Low- to moderate temperature geothermal resource assessment of Nevada, final report : U. S. Department of Energy contract ET- 78-S-08-1556.
Van Houten, F. B, 1956, Reconnaissance of Cenozoic sedimentary rocks of Nevada: Ame rican Association of Petro1eum Geolog i st s Bulletin , v. 40, p. 2801-2825.
Zohdy, A. A. R., Eaton, G. P. and Mabey, O. R., 1974, Ap pli cati on of su r face geophysics t o groundwat er investigations: U.S. Geol ogical Su rvey, Tech niq ues of Wa t er-Resources Investigation, Book 2, Chapte r 01, 116 p.
37
Appendi x A. Maj or and t race element chemical ana lysis of wat er from t he Reynolds we 11, ~~e11 s, Nevada.
103 NV -\HS-1
ELEMENT CO NCENTRATION (PPM)
NA 58 K 20 CA 33 MG 5 FE < 0.025 AL < 0.625 SI 41 TI < 0. 125 p < 0. 625 SR 0.31 BA < 0. 625 V < 1. 25 CR < 0.050 MN < 0. 250 CO < 0.025 NI < 0.1 25 CU < 0.125 MO < 1. 25 PB < 0.2 50 ZN < 0.125 CO < 0.125 AG < 0.050 AU < 0.100 AS < 0.625 SB < 0. 750 Bl < 2.50 U TE